prometheus: drop the frank-primary scrape job (FreeToken exports no /metrics)

FreeToken has no /metrics endpoint — the job scraped 404s forever, a
structural never-green, not an outage (the Lucebox DS4.1 precedent). The
LlmEndpointDown alert regex self-adjusts (frank-.* matches existing series
only). Comments updated; seam now asserts frank-primary's absence. If
FreeToken grows /metrics, re-add the job.

tests/observability_quadlet.bats

@@ -315,31 +315,28 @@ PAIRS
 
 @test "prometheus scrapes every LLM endpoint that exports metrics" {
     # The LLM endpoints are the services whose behaviour this fleet argues about
-    # most (KV pressure, prefix-cache reuse, queue depth). All three export
-    # the llamacpp:* family since 2026-09-26, when frank-primary (Dankserver)
-    # went back to llama.cpp — the unsloth b11030-mix prebuilt serving
-    # Qwen3.8-Flash-Next Q8_0 — after two days of the Lucebox DS4.1 engine,
-    # which exported nothing (404) and had no job.
+    # most (KV pressure, prefix-cache reuse, queue depth). Both Dankclaw
+    # endpoints export the llamacpp:* family. frank-primary LEFT the set
+    # 2026-10-05: the FreeToken PR587 ROCm engine has NO /metrics endpoint —
+    # scraping it was a structural never-green (404), so the job was deleted
+    # rather than left vacuous (the Lucebox DS4.1 precedent, 2026-09-26).
     # The two Dankclaw endpoints are HOST processes reached through
     # host.containers.internal: this Prometheus is a bridge-networked
     # container, and on this netavark host a container can only reach the
     # host's LAN IP at a PUBLISHED port — a host-process bind like
     # llama-server's 0.0.0.0:7770 is refused at 192.168.0.143:7770 while it
     # answers at 169.254.1.2:7770 (why frank-small stayed red by construction
-    # for days until the 2026-09-20 /targets audit). frank-primary is a
-    # DIFFERENT machine, so that quirk does not apply: plain LAN routing
-    # reaches 192.168.0.235:7770, and the job must say so (a gateway target
-    # would point at Dankclaw's own :7770 — frank-large — and double-scrape
-    # it under the wrong label).
+    # for days until the 2026-09-20 /targets audit).
     local cfg="$REPO_ROOT/shared/prometheus/prometheus.yml"
     grep -q '"host.containers.internal:7771"' "$cfg" || { echo "frank-small not scraped"; return 1; }
     grep -q '"host.containers.internal:7770"' "$cfg" || { echo "frank-large not scraped"; return 1; }
-    grep -q '"192.168.0.235:7770"' "$cfg" || { echo "frank-primary not scraped"; return 1; }
+    ! grep -q '"192.168.0.235:7770"' "$cfg"
     grep -q '"host.containers.internal:7770,192.168.0.235:7770"' "$cfg" \
         && { echo "frank-primary folded into a Dankclaw gateway target"; return 1; }
-    for job in frank-small frank-large frank-primary; do
+    for job in frank-small frank-large; do
         grep -q "job_name: \"$job\"" "$cfg" || { echo "no scrape job for $job"; return 1; }
     done
+    ! grep -q 'job_name: "frank-primary"' "$cfg"
     # None of them is reached through a guarded vhost: Prometheus cannot solve
     # an Anubis challenge, so a franksdank.cloud target is red by construction.
     ! grep -qE '^\s*-\s*"?https?://[^"]*franksdank' "$cfg"